The following results were delivered in the analysis of the ignitability and combustibility and the general properties of MFO (marine fuel oil) based on IP541. There is a relation where the ECN (estimated cetane number) becomes lower as CCAI (calculated carbon aromaticitv index) becomes higher. However, there are cases where ECN is low even if CCAI is lower than 850, and it was confirmed that the number of problem cases in such ranges is relatively high. Regarding MFO with viscosity grade of 180 and 380cSt, it was confirmed that ECN becomes lower as the sulfur content becomes lower. In addition, there are many cases of poor ignition properties in MFO with low sulfur content, and few cases of high ECN. About 80% of the cases of combustion trouble in the diesel engine of actual ships corresponded to ECN of 20 or below. It was shown that it is possible to identify combustion trouble areas if ECN=20 taken as a criterion. However, there were still some cases in which the distinction between normal oil and trouble inducible oil was not possible. Regarding the relation between the FIA-CN (FIA celane number) and ECN, the experimentally obtained ECN values of MFO were higher than those obtained from the conversion formula for ECN values higher than 15 and lower than those of the conversion formula for ECN values lower than 15. Next, a multivariate analysis was introduced as a practical evaluation method of MFO quality, and the following results were delivered by evaluation with the MTS (Mahalanobis-Taguchi system). As a result of selecting the groups of variables, it was found that apart from the ignition delay, the initial peak of ROHR (rate of heat release) and the afterburning gradient, as well as the general properties such as MCR and density, contribute to the determination. Since trouble inducible oil was also seen in the distribution area of normal oil, in the present research the probability of correct identification of trouble inducible oil was limited to 65%. However, since trouble inducible oil was easily identified on the basis of its long Mahalanobis distance by using MTS analysis, MTS is regarded as an effective analytical method. The ignitability of MFO can be expected to deteriorate in the future due to the requirements for reduction of sulfur content in accordance with future regulations. In order to ensure sufficient quality management for MFO, it is considered necessary to perform an analysis of the ignitability and combustibility in addition to the conventional general properties analysis. Furthermore, in regard to evaluation methods of MFO quality based on MTS analysis, it is important to introduce even more effective variables and to perform evaluation in regard to other viscosity grades, as well as to improve the accuracy of the measurements.
Recent trend of marine residual fuel oil and analysis by FCA, constant volume combustion chamber method (IP541)
2009
8 Seiten, 13 Bilder, 1 Tabelle, 13 Quellen
Aufsatz (Konferenz)
Englisch
Schiff , Schweröl , Treibstoff , Entzündbarkeit , Verbrennbarkeit , Cetanzahl , Viskosität , Zusammensetzung , Dichte , Analytik , Brennverlauf
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